Efficient random access in a wireless telecommunication system

Abstract

A wireless communication device is operated to transmit information on a random access channel of a network node. Operation involves determining a first transmit power level for a transmission of the information, and selecting a first transmission time for the transmission of the information, wherein the selected first transmission time is determined by a number drawn from a first contention window, and wherein the selected first transmission time corresponds to a first amount of time delay that must elapse before transmission of the information occurs. The information is transmitted at the selected first transmission time, at the first transmit power level. When the transmitted information was not successfully received by the network node, a size of a second contention window is determined based on a size of the first contention window and on the first transmit power level. A second transmission time is selected for the transmission of the information, wherein the selected second transmission time is determined by a number drawn from the second contention window and wherein the selected second transmission time corresponds to a second amount of time delay that must elapse before transmission of the information occurs. The information is transmitted at the selected second transmission time, at a second transmit power level.

1 . A method of operating a wireless communication device to transmit information on a random access channel of a network node, the method comprising:
 determining a first transmit power level for a transmission of the information by randomly selecting the first transmit power level from a plurality of fixed power levels;   selecting a first transmission time for the transmission of the information, wherein the selected first transmission time is determined by a number drawn from a first contention window, and wherein the selected first transmission time corresponds to a first amount of time delay that must elapse before transmission of the information occurs;   at the selected first transmission time, transmitting the information at the first transmit power level;   when the transmitted information was not successfully received by the network node, determining a size of a second contention window based on a size of the first contention window and on the first transmit power level;   selecting a second transmission time for the transmission of the information, wherein the selected second transmission time is determined by a number drawn from the second contention window and wherein the selected second transmission time corresponds to a second amount of time delay that must elapse before transmission of the information occurs; and   at the selected second transmission time, transmitting the information at a second transmit power level,   wherein the second transmit power level is randomly selected from among members of the plurality of fixed power levels that are greater than the first transmit power level.   
     
     
         2 - 3 . (canceled) 
     
     
         4 . The method of  claim 1 , comprising:
 receiving power level information from the network node; and   using the received power level information to determine the first transmit power level.   
     
     
         5 . The method of  claim 4 , wherein using the received power level information to determine the first transmit power level comprises:
 using the received power level information to determine a minimum transmit power level; and   selecting the first transmit power level from one or more power levels that are at or above the minimum transmit power level.   
     
     
         6 . The method of  claim 5 , wherein:
 the one or more power levels that are at or above the minimum transmit power level comprise at least two transmit power levels, and   selecting the first transmit power level from the one or more power levels that are at or above the minimum transmit power level comprises randomly selecting one of the at least two transmit power levels.   
     
     
         7 . The method of  claim 4 , wherein the received power level information is a target receive power level, and wherein the method comprises:
 using information about the random access channel to determine the first transmit power level such that it will cause transmitted information to be received at or above the target receive power level at the network node.   
     
     
         8 . (canceled) 
     
     
         9 . The method of  claim 1 , wherein a difference between any two of the plurality of fixed power levels is at least 5 dB. 
     
     
         10 . The method of  claim 9 , wherein selecting the first transmit power level from the plurality of fixed power levels comprises selecting the first transmit power level from only the fixed power levels that satisfy a required link budget for transmission on the random access channel to the network node. 
     
     
         11 . The method of  claim 10 , comprising:
 determining the required link budget for the transmission on the random access channel to the network node by estimating a pathloss on the random access channel between the wireless communication device and the network node.   
     
     
         12 - 13 . (canceled) 
     
     
         14 - 15 . (canceled) 
     
     
         16 . The method of  claim 1 , wherein selecting the first transmission time for the transmission of the information comprises randomly selecting a transmission time falling within the first contention window. 
     
     
         17 . The method of  claim 1 , wherein the size of the second contention window is larger than the size of the first contention window. 
     
     
         18 . The method of  claim 1 , wherein the wireless communication device performs all transmissions on the random access channel in compliance with IEEE 802.11 standards. 
     
     
         19 - 25 . (canceled) 
     
     
         26 . An apparatus for operating a wireless communication device to transmit information on a random access channel of a network node, the apparatus comprising:
 circuitry configured to determine a first transmit power level for a transmission of the information by randomly selecting the first transmit power level from a plurality of fixed power levels;   circuitry configured to select a first transmission time for the transmission of the information, wherein the selected first transmission time is determined by a number drawn from a first contention window, and wherein the selected first transmission time corresponds to a first amount of time delay that must elapse before transmission of the information occurs;   circuitry configured to transmit the information at the first transmit power level at the selected first transmission time;   circuitry configured to determine, when the transmitted information was not successfully received by the network node, a size of a second contention window based on a size of the first contention window and on the first transmit power level;   circuitry configured to select a second transmission time for the transmission of the information, wherein the selected second transmission time is determined by a number drawn from the second contention window and wherein the selected second transmission time corresponds to a second amount of time delay that must elapse before transmission of the information occurs;   circuitry configured to transmit the information at a second transmit power level, at the selected second transmission time; and   circuitry configured to randomly select the second transmit power level from among members of the plurality of fixed power levels that are greater than the first transmit power level.   
     
     
         27 - 28 . (canceled) 
     
     
         29 . The apparatus of  claim 26 , comprising:
 circuitry configured to receive power level information from the network node; and   circuitry configured to use the received power level information to determine the first transmit power level.   
     
     
         30 . The apparatus of  claim 29 , wherein the circuitry configured to use the received power level information to determine the first transmit power level comprises:
 circuitry configured to use the received power level information to determine a minimum transmit power level; and   circuitry configured to select the first transmit power level from one or more power levels that are at or above the minimum transmit power level.   
     
     
         31 . The apparatus of  claim 30 , wherein:
 the one or more power levels that are at or above the minimum transmit power level comprise at least two transmit power levels, and   the circuitry configured to select the first transmit power level from the one or more power levels that are at or above the minimum transmit power level comprises circuitry configured to randomly select one of the at least two transmit power levels.   
     
     
         32 . The apparatus of  claim 29 , wherein the received power level information is a target receive power level, and wherein the apparatus comprises:
 circuitry configured to use information about the random access channel to determine the first transmit power level such that it will cause transmitted information to be received at or above the target receive power level at the network node.   
     
     
         33 . (canceled) 
     
     
         34 . The apparatus of  claim 26 , wherein a difference between any two of the plurality of fixed power levels is at least 5 dB. 
     
     
         35 . The apparatus of  claim 34 , wherein the circuitry configured to select the first transmit power level from the plurality of fixed power levels comprises circuitry configured to select the first transmit power level from only the fixed power levels that satisfy a required link budget for transmission on the random access channel to the network node. 
     
     
         36 . The apparatus of  claim 35 , comprising:
 circuitry configured to determine the required link budget for the transmission on the random access channel to the network node by estimating a pathloss on the random access channel between the wireless communication device and the network node.   
     
     
         37 - 38 . (canceled) 
     
     
         39 - 40 . (canceled) 
     
     
         41 . The apparatus of  claim 26 , wherein the circuitry configured to select the first transmission time for the transmission of the information comprises circuitry configured to randomly select a transmission time falling within the first contention window. 
     
     
         42 . The apparatus of  claim 26 , wherein the size of the second contention window is larger than the size of the first contention window. 
     
     
         43 . The apparatus of  claim 26 , wherein the wireless communication device performs all transmissions on the random access channel in compliance with IEEE 802.11 standards. 
     
     
         44 .- 48 . (canceled)